1. Technical Field
The present invention relates to an image forming apparatus and an image forming method employing an electrostatic recording method.
2. Related Art
Conventionally, in a recording apparatus which obtains a color image by an electrographic process, a color image is obtained by developing three primary colors according to respective image data, and sequentially superposing these toner images. As to a specific structure of the apparatus, there is known: a so-called four cycle apparatus which develops each color in one photoreceptor drum formed with a latent image by an image forming method, and repeats transferring the colors onto transfer members, so as to obtain a color image; or a tandem apparatus which comprises photoreceptor drums and development units per image forming device of respective colors, and sequentially and continuously transfers toner images by the movement of transfer members, so as to obtain a color image.
These are common at least in having a plurality of development units per respective colors. Therefore, in a normal color image formation, four development units for three primary colors plus black are required. Furthermore, a tandem apparatus requires four photoreceptor drums according to the respective four development units, and a device which matches the synchronization of these four image forming units. Thus, it is inevitable to increase the size and the cost of the apparatus.